Electrical relay



p 1947'. A. HUFNAGEL 2,426,970

ELECTRICAL RELAY Filed June 28, 1944 3 Sheets-Sheet 1 'III III

4.6 I fly INVENTOR A iza Pew Half/@1290]. BY aid Wi lflJ A TTOR N E 3 Sept. 2, 1947. A. HUFNAGEL 2,426,970

ELECTRICAL RELAY Filed June 28, 1944 3 Sheets-Sheet 2 4.5 I Z 45 INVENTOR Andrew Hal/wage! BY auzrwa HIJ ATTORNEY Sept. 2, 1947. A. HUFNAGEL ELECTRICAL RELAY Filed June 28, 1944 3 Sheets-Sheet 3 INVEN'fOR A12 dPQw Hufnagel Hi1 ATTORNEY Patented Sept. 2, 1947 ELECTRICAL RELAY Andrew Hufnagel, Penn Township, Allegheny County, Pa., assignor to The Union Switch & Signal Company, Swissvale, Pa., a corporation of Pennsylvania Application June 28, 1944, Serial No. 542,561

4 Claims.

My invention relates to electrical relays, and particularly to electrical relays which are suit able for use in railway signaling systems employing for the control of signaling devices current which is periodically interrupted or coded at different frequencies in accordance with traffic conditions. V

More particularly, my present invention relates to relays of the type described in Letters Patent of the United States No. 2,300,790, granted to Robert M. Laurenson on November 3, 1942, in which the rate of operation of the relay when the relay is energized is determined by the period of oscillation of a relatively massive compound pendulum, and one object of my present invention is to provide an improved bearing for supporting the pendulum in relays of the type disclosed in said patent, which bearing shall have negligible friction and extremely long life.

Another object of my invention is to provide a bearing for supporting the pendulum in relays f the type described, which bearing will be inexpensive to manufacture and install, and which will not require an maintenance throughout the life of the relay.

Another object of my invention is to provide improved means for operatively connecting the pendulum of relays of the type described with the contact carrying rocker of the relay.

A further object of my invention is to provide means to limit the amplitude of the pendulum while oscillating, and at the same time enable the pendulum to start oscillating at a relatively low energization of the relay.

According to my invention the bearing oomprises a horizontal shaft which is secured intermediate its ends to the pendulum and which is provided at each end with a trunnion supported on bearing tracks formed on the upper ends of bearing arms the lower ends of which arms each include a flexible supporting strip. The bearing arms are inclined toward the shaft so that the planes of the arms intersect substantially at the I axis of the associated trunnion, and the bearing tracks are so disposed that they are substantially normal with respect to the plane of the arms. When the pendulum i moved in either direction from its gravity biased position, frictional adhesion between the trunnions and bearing track causes the tracks to move with the trunnions in such manner that substantially pure rolling motion results, the necessary motion of the tracks being permitted by the flexing of the flexible strips of the bearing arms. End play of the pendulum is limited v by adjustable positioning members which cooperate with the ends of the trunnions, while excessive vertical displacement of the pendulum is prevented by holes in the frame which serves as a support for the relay parts and which holes receive the shaft between the trunnions with some clearance.

The pendulum is operatively connected with a rocker which'carries the contacts of the relay through the medium of a semi-flexible arm which is secured to and depends from the rocker. An angle bracket is mounted on the lower end of this arm by means of insulating supports and has attached to the horizontal portion thereof two flexible supporting strips which extend transversely of the relay directly above a circular driving rod secured to the pendulum some distance above the pivotal axis of the pendulum. Each of these strip carries a rigid finger which extends downwardly from thefree end of the strip at a slight angle towardthe other finger and which is pro vided at its free end with a curved surface which cooperates Withthe driving rod. The parts are so proportioned that the two curved surfaces are held in frictional engagement with the opposite sides of the driving rod by a slight flexing of the supporting strips and that as the pendulum oscillates the movement of the pendulum will cause the rod to roll around the curved surfaces of the fingers and thus transmit the motion of the pendulum through the fingers to the flexible supporting strips, and thence through the angle bracket and the depending armto the rocker whereby the rocker is caused to oscillate in synchronism with the oscillations of the pendulum.

The pendulum is caused to oscillate by an electromagnetenergized over certain ones of the relay contacts, and provided with pole pieces which cooperate with an armature attached to the pendulum. Associated with the armature is a U-shaped extension of soft steel which is thin enough to saturate under starting conditions,

and which acts to change the inductanceof the electromagnet with changes in amplitude of the pendulum in a manner which tends to limit the pendulumamplitude. l

Fig. 3 is a View partly in elevation, partly in section and partly diagrammatic of certain parts of the relay shown in Figs. 1 and 2. Fig. 4 is a sectional view taken on the line IV-IV of Fig. 3.

Similar reference characters refer to similar parts in all four views.

Referring to the drawings, the relay here shown is generally similar to the relay described and. claimed in the aforementioned Laurenson Patent No. 2,300,790 except for the bearing means presently to be described for supportingthe compound;

pendulum of the relay, and certain other im.-. provement which will also be described presently.

The relay as shown comprises a contact carrying rocker I of suitable-insulating material, such as a phenol condensation product, suspended by means of flexible strips 2 from a top plate 3, also of suitable insulating material. The rocker I is provided with a plurality of flexible contact fingers 4 and 5-, each ofwhich'cooperates with a fixed contact member 4a or 50! toclose a contact 4--4a or 5-511 according as the-rocker is swung to one or the other of its extreme positions. The contacts are disposed in pairs andare secured to the opposite sides of the rocker within vertical grooves which maintain the fingers in the desired vertical positions by means of bolts Ii which extend through suitable holes in the'rocker and the fingers and are secured=in place by nuts I. The bolts 6 also serve to securethe lower ends of the strips 2 tothe rocker thereby electrically connecting the fingers with the strips; The upper ends of the strips are securedto the heads of terminal. posts 8 mounted on the top plate I. The positions of the flexiblefingers when the fingers are out ofengagement with the associated fixed contact members are determined by means of stops 9 whichare clamped against-the outer faces of the fingers bymeans of the associated bolts 6 and whichare so adjustedby bending; them that the fingers will break the contacts-in the desired positions in response to theswingingmovement of thecontact carrying rocker I'.

The fixed contact members 4a and 5a aresimilar to the fixed contact members Illa and. I 9a described and claimed in Letters Patent of the.

United States No. 2,285,890, granted to Herman G, Blosser on June 9, 1942, for Electrical relays, and are adjustablysecured to the lower ends of terminal studs Ill mounted on; the top plate. on opposite sides of the terminalpost Bin a manner which is similar to that described in the said'patent. It is believedtobe unnecessary, therefore, to describe the construction and arrangement of thesefixed contact members any further'herein. It should be noted, however, that due to the fact that these fixed contact members are adjustable, the contacts can be readily adjusted to be either openor closed when the rocker isatrestand to close or open atany point' in the stroke of the rocker I.

The relay alsocomprises motor means for oscillating the rocker between its two extreme positions to alternately operate thecontacts ata constant relatively low preselected frequency. As here shown these motor means comprise an electromagnet C having pole ieces Ho and Ill; secured by means of studs I2 to the plate portions I3a and I3b of a frame I3 in parallel spaced relation and connected together at one end by a core I4 surrounded by a winding I5.

The frame I3 is in the form of a one piece rectangular casting provided at its upper end with spaced parallel arms I30 and I3d which support the top plate I, and at its lower end with a connecting portion I3e. Substantially V-shaped openings I3f' are formed in the plate portions below and between the arms to provide access to certain of the operating parts of the relay for inspection or repair.

The pole pieces II a and II b of electromagnet C cooperate at their lower or free ends with a magnetizable. armature I8 which is secured to one side of the lower portion or foot of a compound pendulum P, and with a saturable armatureextension. I; of soft steel which is clamped againstthe outer face of the armature I8 for a purpose which will be made clear presently.

The compound pendulum P may have any suitable form possessing withinthelimited space available the necessary mass to cause it tohave a natural period equal to-the desired code frequency, which may forexamplebe-75 cyclesper minute. In the form here illustratedthis pendulum comprises a castingconsisting of" a central. horizontal portion 20 provided at its opposite ends witlr upstanding weight arms 20a, and provided.

intermediate its ends at oneside of said horizontal portion with acentral depending leg'"20b the center of gravity of the pendulum; and the trunnions 22a each rest on a pair of crossed bearing tracks 23*providedon the upper ends of laterally offset bearing arms 24; arms are inclined toward the shaft, so that the planesof thearms intersect substantially-atthe axis of the shaft, and are eachprovided at their lower ends with a flexible supporting strip 21 which is secured at its lower end by' means of an associated stud 25- and clampingblock' 26 to an inclined surface I3h formed ona bearing mounting block 45 Thebloeks 45 are clamped by means ofstuds 46- against flat surfaces groundon the connecting portion I3e of the casting I3: The upper edgeof eachclamping block 20 is rounded into a gradual curve and the opposite portion of the surface I3? is similarly rounded to cause the supporting strip 21- to flex in the form of a gradual curve inresponse to movement of the bearing armsdue to operation of" the pendulum. The bearing tracks are so-disposed thatthey are substantiallynormal to the-planeof thearms, and theangles at which the arms are disposed are such and the parts are someportioned that when the pendulum is moved ineither direction-from its gravity biased position;

the frictional adhesion between the trunnions and bearing trackswillcause the tracksto move.

with the trunnion in such manner that substantiallypurerolling motion results, the necessary The bearing motion of the tracks being permitted by the flexing of the flexible supporting strips. It will be seen, therefore, that oscillation of the pendulum will cause a new line of contact to be formed between each trunnion and each track in each different angular position of the pendulum throughout its entire angular movement.

The pendulum i maintained in the desired longitudinal and lateral position relative to the bearing tracks and to the pole pieces Ha and Ilb by means of adjustable positioning members 30 and 3|. These members are secured at their lower ends to the bearing mounting blocks 45 by means of studs 32, and extend upwardly past the trunnions 22a to positions a slight distance above the trunnions. Each positioning member is provided intermediate its ends with a hole 3|a through which a stud 33 secured to the adjacent plate portion [3a or I32) of the frame extends with some clearance, and mounted on this stud on opposite sides of the positioning member are adjusting. nuts 34 and 35. It will be obvious that by adjusting these nuts the upper ends of the positioning member can be moved toward or away from the associated plate portions 13a and 13b of the frame I3, and these nuts are intended to be so adjusted that when the pendulum is in the proper longitudinal position, the positioning members will just clear the ends of the shaft. Toreduce friction and wear the ends of the shaft are rounded and chromium plated, and the upper ends of the positioning members are likewise chromium plated.

Excessive .vertical and lateral displacement of the pendulum P from its normal position is prevented by passing the shaft 22 adjacent the inner ends of the trunnions 22a through clearance holes I37 provided in the plate portions [3a and l3b of the frame 13. The studs 46 which securing the bearing mounting blocks 45 in place pass through clearance holes in the bearing mounting blocks, and these clearance holes are made sufficiently large so that each bearing assembly may be moved about as a unit before being secured in place an amount which will permit the pendulum shaft to be centered in the holes I39. It will be obvious that the holes l39' do not interfere in any way with the normal operation of the pendulum, but that, if due to handling or the like abnormal forces areexerted on the pendulum, the shaft will engage the frame at the edges of the holes and will thus act to limit the displacement of the pendulum to an amount which is insuflicient to cause damage to the parts.

The pendulum P is operatively connected with the rocker I through the medium of an arm 31 the upper end of which is clamped to the center of the rocker by means of one of the bolts 6. An angle bracket 40 is mounted on the lower end of the arm 31 by means of insulating supports 39, and has attached to the horizontal portion thereof two flexible supporting strips M and 42 which extend transversely of the relay above and on opposite sides of a circular drive rod 38 mounted at its ends in aligned sleeves 33a screwed through the sides of the arms 20a of the pendulum directly above the shaft 22. The supporting strips 41 and 42 support two driving fingers 43 and 44. These finger are secured to the outer ends of the strips as by riveting, and are inclined downwardly away from the strips and are provided at their free ends with confronting curved surfaces 43a and 43b disposed on opposite sides of the driving rod 38. portioned that when the pendulum is at rest, the

The parts are so prosupporting strips will be bowed just enough to hold the curved surfaces of the driving fingers in frictional engagement with the driving rod, and. that when the pendulum is in motion the resulting movement of the driving rod will cause it to move along the curved surface of the fingers with a pure rolling motion and thus transmit the motion of the pendulum from the rod through the fingers to the flexible supportin strips and thence through the angle bracket and the depending arm 31 to the rocker, whereby the rocker is caused to oscillate in synchronism with the oscillations of the pendulum. It should be noted that the movement of the driving fingers necessary to permit the driving rod to roll along the curved surfaces results in a flexing of the supporting strips, which strips are made sufficiently flexible to permit the necessary flexing to take place without causing slippage between the driving rod and the driving fingers.

With the pendulum operatively connected with the rocker in the manner just described it will be apparent that rotation of the pendulum in one direction will cause swinging movement of the rocker in the opposite direction, and the parts are further so proportioned that oscillation of the pendulum through its normal amplitude will cause movement of the rocker between its two extreme positions. The length of the pendulum P is such that the armature I8 and armature extension l8a are free to swing between the pole pieces I la and H79, and it will be seen, therefore, that energization of the winding l5 will tend to pull the armature l8 between the pole pieces and hence will swing the rocker in a, clockwise direction. as viewed in Figs. 1 and 3. The energization of the winding I5 may be controlled by one set of the contacts 44a and 5-511 connected in series with the winding, as shown diagrammatically in Fig. 3. The contacts of this particular set are so adjusted that both contacts 44a and 55a are closed when the pendulum occupies its gravity biased position but that when the pendulum is swung away from this position, one or the other of these contacts will become opened at a predetermined intermediate point in the stroke of the pendulum depending upon which direction the pendulum is swung.

When the pendulum is at rest and energy is initially applied to the winding I5 magnetic fiux will traverse the air gap at each end of the armature. Due to the pole piece extension lBa this flux will divide into two parts designated F! and F2, respectively, in Fig. 4. It is obvious that the flux lines designated Fl will tend to cause the armature to swing between the pole pieces, and if the voltage applied to the winding I5 is above a certain critical value the armature will swing far enough to open the contact 44a, whereupon the pendulum will start to oscillate. The flux lines designated F2 will not be effective to cause any movement of the armature, and the polar extension lBa is so proportioned that it will be come saturated at a flux density sufficiently low to prevent the ineffective flux lines from appreciably reducing the value of the effective flux Fl.

Once the pendulum has started to oscillate energy will be applied to the winding [5 during each oscillation for the relatively short period of time during which the contacts 4a and 5a are both closed, and under these conditions the armature extension 18a will act to limit the amplitude of the oscillations. The reasons why the extension |8a acts to limit the pendulum amplitude are thought to be as follows:

a. The. effective. pole face area is. increased. makingthe electromagnet more.inductive, sogthat. its-current. and the magnetic; fiuxbuild up -more slowly. This is particularlytrue at' the point in.

the armaturestroke in which the; contact 4+-4a.

just becomes, closedLsince' in this pOSltiOlhthB pole pieceextension IBa will then be disposedzbetween. the pole; pieces, whereas if. the pole: piece, ex? tension were omitted the air gap between the armature and thepole pieces wouldhe large-and: the rise in fiuxwould. be correspendingly'rapidr b. When the. pendulum: is;v oscillating the: fluxlevels are lower thanon' starting, and.- w-itl'i the;

lower. fluxlevels; saturation of the. armature ex.- tension. ceases to; be. a. factor.

is decreased.

It should be notedthat while the armature extension as shown is. substantially U-shaped;,with

triangular arms or projections. the actual. shape of the arms. is not important provided the-:arms

are kept thin enough to saturate at the proper flux densities.

It will be obvious that OSCilldtiOllxOf thependulum will cause the contacts 4--4a and;5.--5a.whichare not used to control the energization of the winding ii to bealternately opened:.and closed at thefrequency of' oscillationof the pendulum.

These contacts may be used for coding purposesor for any otherdesired purpose as -willbe readily understood;

One advantage of a relay embodying nay-inven-- tion is that the bearing structuredoes not require any oiling. and shows almost; no. detectableywear after long periods of operation.

Another advantage of a relay'embodying my invention is that the bearing structure provides accurate centering of the pendulum with; respect to the electromagnet and contacts. This.

prevents variations in thev voltage required to start the pendulum. oscillating:

A further advantage of a relayembodyingmy' invention is that due to the-small amount. of: friction in theoscillating parts it:is'- highly'efiitcient.

A still further advantage'of a relay embodying my invention is that in spite of the smalliamount'.

of friction in the oscillating: parts any tendency of the pendulum to overswing is .efiectively eliminated, and the pendulumamplitudetremains sub stantially constant over a wide degree of energization of the parts.

Although I have-herein shown: and described only one form of electrical relay'embodyingmy invention, it is understoodthat various changes and modifications may be made thereina within the scope of the appended claims without depart-:-

ing from the spirit and'scope of my inventiona Having thus described my invention, whatl claim is:

1. In combination, a frame-provided with two'- spaced parallel plate portions connectedat'theirlower end with a connecting portion and provided with aligned holes, a compound pendulum comprising a central horizontal portion provided at its opposite ends with upstanding arms and provided intermediate its ends with a central depending leg terminating at" its lower end.

in a foot, a shaft extending throughsaidarms and through the aligned holesin said. plate por tions and provided at its ends with trunnions, a pair of bearing arms extending toward-cachet- 8. saidtrunnions on: opposite sides thereof, each. said. arm: being; secured. at its lower end: to" theconnecting portion: of it said: frame; by means= of a: flexible supporting; strip; and; being provided at.

its. upper enda with: a; bearing, track. extending.

normalto'. the plane. of: thearm in supporting re-- lation to the.associateditrunnionrthe. two tracks on; the arms of. eachpair being :laterally offset, thepartsbeing. so;v proportioned that said shait, is normally held clear 'Ofl said. holes. by engagement. of said. trunnionswith the associated track but that saidsha'ft will engage. said holes and limit vertical. displacements of said pendulum.v in; the event of the: application. of: abnormal forces. to. said. pendulum, means for positioning. saidi pendulum endwise comprising: two. adjusting members secured; at their lowers ends to: said.

frame and providedintermediate theirendswitha means for: moving said-members toward andsaway from said frame;

2; In an electrical relay, the combination. with a -rocker mounted for swinging movement. be.- tween two extreme positions, a. pendulum}. andi motor means-for causing said pendulum tolosa cillate; of meansfor operativelyconnecting said. rocker with said pendulum comprising a rod se-- cured to-saidpendulum above its axis .of: oscillation; anarm secured to said rocker, and: two fingers each provided at one end- 'witha curved surface-andsec-ured at the other end to-thefree end of' said* arm by flexible-means in sucli man'- ner that said curved surfaces are disposed on op posite sides of said rod and are held infrictional engagement with said rod bysaid flexible means, whereby whensaid pendlulum is oscillating" said rod will move-along*said curved surfaces with a rolling motion" and-wilt act totransmit the 0s cillations of said-pendulum to said' roelier.

3; In' anelectricalreiay, the comblnatiorrwitha rocker mounted for swinging movement be tween two extreme positions; a pendulum; and

means for causing said pendulum tooscil late, of a depending-armsecuredto-seid roclier,

a bracket'securedtobutinsulated fromthe lower end of said arm; a drive rodsecured to said pen dulum above'its axis of' oscillation; two-flexible supporting strips secured to said bracket and extending transversely of the relay abo ve ancl on opposite sides of said drive rod; tWUdliVlng fingers secured at oneendto thefree'ends' of" said supporting strips; said strips being inclined downwardly from said supporting strips and'be ing provided at. their free endswith' confront ing surfaces disposed; on' opposite sides of said driving rod, the parts-being so proportioned that when saidpendulum is at restsaid stripswill act-- to hol'dthe curved'surfa'ces' of the-drivingfingers in frictional engagement withv the drivingrod and-that when the pendulum" is in motion the resulting' movement of thedriving rod will cause it tomove along the curved surfaces of said fin"- gers with a pure. rollingjmotion to thereby cause said rockeryto oscillate'in synchronisrn' with the oscillations of said pendulum.

4. In an electrical relay includinganpelectromagnet. providedlwith spaced pole pieces, apendulum armature. disposed to. swing between said; pole pieces,. contacts controlled by said armature, and meanscontrolledfby said contacts for. energizing said electromagnet tocausesaid-pemdulum to oscillate. at its natural periodithe combination of an armature-extensionsecured tosaidv. armature and extending between-.saidpole pieces; saidextensiombeing proportionedtdbeeome sat- 9 urated in response to energization of said elec- Number tromagnet when said armature is at rest but not 1 310 464 when said armature is oscillating. 1429393 ANDREW HUFNAGEL. 150309o REFERENCES CITED 5 1,523,762 22,971 The following references are of record in the 00,021 file of this patent: 1,300,464

UNITED STATES PATENTS 10 Number Name Date Number 1,885,721 Hieber Nov. 1, 1932 257,403

534,833 Johnson Feb. 26, 1895 Name Date Barrett July 22, 1919 Anderson Sept. 19, 1922 Carichofi July 29, 1924 Favre-Bulle Jan. 20, 1925 Minniss Feb. 15, 1859 Richards Mar. 1, 1898 Barrett July 22, 1919 FOREIGN PATENTS Country Date Great Britain Sept. 2, 1926 

